For the blind or visually impaired, the current state of technology, besides guide dogs, includes alternative devices based on mechanical designs (i.e. various types of canes and guide mechanisms) or ultra-sonic technologies. Although the blind and visually impaired have made great strides in education, employment, and information access, they have not benefited from any real breakthroughs in practical and affordable mobility devices that facilitate safe and independent travel outside of the home.
Although users may become very adept with a “pure” mechanical device, such as the traditional “long cane” or “white cane,” there are inherent limitations to its use, most notably the requirement that the device actually touch the obstacle by a “swipe” or a “thrusting” or “probing” technique. This fact can put the person in considerable danger, even if successfully employed since typically, the probing motions are limited to close, ground-level obstacles.
Some recent attempts to improve upon the use of canes, involve the use of ultrasound. See, for example, U.S. Pat. No. 6,469,956, herein incorporated by reference. Scanning with an ultrasound wide beam will not easily find openings, especially from a distance. The device for generating an ultrasound beam is conical in shape, about 48 inches in diameter at 14 feet. Wind and temperature changes affect the ultrasound beam and will give false distances and alarms. If approaching an obstacle at less than 45° degrees, the ultra sonic signal tends to miss the obstacle because it is reflected away from smooth surfaces (e.g., smooth walls, and some smooth, contoured obstacles) and is a known disadvantage of ultra sonic detection devices in general. Thus, the typical ultra-sonic devices that have been marketed are simply not reliable enough to inspire the trust necessary for a blind person to rely on the sensory signals (i.e. sounds, musical notes, etc.) thereby negating one of the major positives to be expected from a primary visual assistance device, namely, a growing sense of self-confidence and trust in the device.
Use of guide or companion dogs has provided some people with increased mobility and self-sufficiency, but this benefit is limited to a small potion of the overall potential patient population for many reasons. Although guide dogs enjoy tremendous support among the general public as well as among the visually impaired population, there are a significant number of people who cannot use a guide dog or who cannot cope with some of the disadvantages inherent in using a “sight instrument” with independent action capabilities. Many people are allergic to, or don't like, dogs or their feed/grooming aids, and caring for the dog presents stresses and challenges that many vision and mobility impaired people are not able to handle without constant assistance from a sighted person. Dogs, just like people, have personalities which can be difficult to “match” and they also get sick, infirm and die, creating serious emotional and practical challenges.
An object of this invention is to provide an effective obstacle detection accessory to smart mobile electronic systems, such as portable game systems and mobile phones, for assisting the visually impaired at low cost.